Mattress, provided with spring elements, such as coil springs

ABSTRACT

The present invention relates to a mattress ( 10 ), for use as a bed, which mattress comprises substantially resilient material such as a foam rubber, spring devices ( 4 ) such as coil springs being provided in the mattress, in order to distribute the pressure exerted upon the mattress. The mattress according to the invention is characterised in that the mattress comprises at least two layers ( 1,2 ) placed one on top of the other, blind holes ( 3 ) for the accommodation of the spring devices ( 4 ) being made in at least one of said two layers, which blind holes connect to the boundary face between the two layers.

The invention relates to a mattress, for use as a bed, which mattresscomprises substantially resilient material such as a foam rubber, springdevices such as coil springs being provided in the mattress, in order todistribute the pressure exerted upon the mattress.

For the purpose of clarity, it is pointed out that the term “mattress”in the present text is intended to convey substantially resilientelements for use as a bed, cushion, chair or comparable objects.

A mattress according to the type mentioned in the preamble is known inthe prior art. According to the prior art, it is known to bore from thetop side of the mattress, using a drill that resembles an apple corer,and remove a usually round cylindrical part from the mattress. After theremoval of this cylindrical element, a spring element, such as a coilspring, is screwed into the blind hole formed in this way in thematerial of the mattress, the entire spring element being concealed inthe material of the mattress. The blind hole is subsequently closed upagain with the cylindrical part originally removed.

The fitting of the spring devices according to the prior art has anumber of disadvantages. First, at least one side of the mattress has tobe damaged over a great part of its surface, in order to be able to fitthe spring devices in the material of the mattress. Secondly, thefunctioning of the spring devices fitted in the material of the mattressis limited. The spring elements are in fact enclosed on all sides by thematerial of the mattress, so that a major part of the springcharacteristic is determined by the material of the mattress, and a usercannot adjust the spring characteristic of the spring elements asdesired.

It is the object of the present invention to provide a mattress of thetype mentioned in the preamble, in the case of which the disadvantagesindicated above are avoided as far as possible.

That object is achieved according to the invention by the fact that themattress comprises at least two layers provided one on top of the other,blind holes for the accommodation of the spring devices being providedin at least one of said two layers, which blind holes connect to theboundary face between the two layers.

In this case it is possible for the blind holes to be made in each ofthe two layers.

By constructing the mattress from a first layer and a second layer, itis possible to form a mattress that is free from damage both on the topside and on the bottom side. A boundary face that extends up to the sideedges of the mattress will be present between the two layers ofmaterial. The boundary face can be seen and also felt on said side edgesof the mattress. Since a user does not come into contact with said sideedges of the mattress, the presence of such a boundary face during useis not a problem.

By means of the abovementioned measures, it is further ensured that thespring devices extend in a channel made in the mattress. In other words,the spring devices are not enclosed on all sides by the material of themattress, and can therefore perform their spring action better.

It appears from research carried out by the applicant that fitting thespring devices in the manner described above ensures that the pressuredistribution that is exerted upon the body of a user is better than thatin the case of mattresses according to the prior art.

According to the invention, it is further possible for the blind holesin the first layer to connect to the blind holes in the second layer, inorder to form channels in the mattress that extend through both thefirst and the second layer.

By means of this measure it is possible for spring devices that extendin both layers of the mattress to be placed in the mattress. Through thepresence of the blind holes in the two layers, the spring devices areenclosed on both their sides in the material of the mattress.

According to the invention, it is further possible for the first layerto comprise a first material and the second layer to comprise a secondmaterial, the first material and the second material being differentfrom each other.

By means of this measure it is possible to vary the sleeping comfortexperienced by the user, simply by turning over the mattress. By usingtwo different types of materials, the mattress can acquire a top sideand a bottom side with differing levels of comfort.

It is also possible by this measure to provide the mattress with a firstside which forms the top side of the mattress when it is in use. Thatmeans that a user makes contact only with that top side. That top sidecan be made of a more expensive material, which has greater comfortrequirements than the material forming the bottom side of the mattress.Through the use of two materials, a saving can be made on the productioncosts of the mattress according to the invention.

According to the invention, it is possible for at least one of thelayers to comprise slow foam.

In the present text the term “slow foam” is intended to convey a type ofplastic material. An example of a material that can be used for themattress according to the invention is slow foam V50.

In order further to improve the distribution of the pressure that isexerted upon the top side of the mattress, it is possible for notches tobe made in the slow foam on the outside of the mattress, which notchesextend in the longitudinal direction and/or the transverse direction ofthe mattress. It is possible here for the notches to extend along alength of approximately 40 mm.

It is also possible according to the invention for at least one of thelayers to comprise polyester.

If there is a desire to provide the mattress with a genuine bottom sideand a genuine top side, it is possible to make the bottom side of arelatively cheap material. The comfort requirements to be made of thismaterial will be less than the requirements to be made of the top side.A suitable layer that could be used for the bottom side is a cold foamof the code name SG45110, commonly used in the prior art.

It is possible according to the invention for spring devices to bedistributed over the mattress, the spring characteristic of the springsvarying along the length of the mattress.

When the mattress is in use, a person will exert pressures of differentmagnitudes upon different points of the mattress. For instance, morepressure will be exerted upon the mattress at the level of the hips thanat the level of the feet. By means of the abovementioned measure it ispossible to adapt the spring characteristic of the springs used in sucha way that optimum pressure distribution is experienced along thelongitudinal direction of the mattress. It is possible in this case forthe mattress to comprise a head end specifically intended for thatpurpose and a foot end specifically intended for that purpose.

It is further possible according to the invention for the spring devicesto comprise a spring element such as a coil spring, and a shock absorberthat is operatively connected to the spring element.

As already indicated above, through the presence of open channels in themattress it is possible to make optimum use of the springcharacteristics of the spring devices used. The distribution of thepressure over the surface of the mattress can be improved further byconstructing the spring devices from a spring element such as a coilspring, combined with a shock absorber. The good pressure distributionthat can be achieved by means of the spring devices in the shockabsorbers means that it is possible for the comfort experienced by theuser to increase further. The chance of damage to or irritation of theskin or other parts of the human body caused by excessive local pressureon the skin is substantially reduced by the presence of the springdevices according to the invention discussed above.

According to a first embodiment, it is possible for the shock absorberto be designed in the form of a substantially continuous element ofresilient material, such as a foam rubber. It is possible here for theshock absorber to comprise polyether. As an alternative, it is possiblefor the shock absorber to comprise a rubber element. The shock absorbercan also comprise an air cylinder.

The use of the various embodiments of the shock absorbers will depend onthe pressure distribution that one desires to achieve in the mattress.

It is further possible according to the invention for the spring devicesto comprise dish-shaped end elements on their ends. In this case theshock absorber can be fixed at both its ends to the end elements of thespring devices.

The presence of the end elements will help to ensure that the springelements and/or the shock absorbers cannot exert local pressure upon thematerial of the mattress. Through the presence of the end elements, thepressure is always distributed over a surface area that corresponds atleast to the surface area of the end element itself. For goodfunctioning of the shock absorbers of the spring devices, it isdesirable for the ends of the shock absorbers to be fixed at a specificplace in the mattress. The shock absorbers can be fixed at both ends tothe end elements, and by way of the end elements can act upon thematerial of the mattress.

When the mattress is in use, at least the top surface of the mattresswill deform under the pressure exerted upon it by a user. It istherefore advantageous for the shock absorber to be hingedly connectedto at least one of the end elements of the spring devices.

Just as stated above with reference to the variation of the springcharacteristics, it is possible according to the invention to vary thespring characteristic of the shock absorber along the length of themattress.

In a second aspect, the invention is aimed at a spring device, for usein a mattress according to one of the preceding claims, the springdevice comprising a spring element such as a coil spring, and a shockabsorber that is operatively connected to the spring element.

The present invention further relates to a method for producing amattress, for use as a bed, the mattress being made of substantiallyresilient material such as foam rubber, and spring devices such as coilsprings being fitted in the mattress, for the distribution of pressureexerted upon the mattress.

The method according to the invention is characterized in that themattress is constructed of at least two layers placed one on top of theother, blind holes being made in at least one of the layers, and springelements being provided in the blind holes, after which the blind holesare covered by the second layer of the mattress. The method according tothe present invention is further improved by the fact that blind holesare provided in both a first and a second layer of the mattress, andspring devices are subsequently provided in the blind holes of the firstlayer of the mattress, the spring devices then being covered by thesecond layer of the mattress, so that the blind holes of the first layerof the mattress lie in line with the blind holes of the second layer ofthe mattress.

The invention will be described further with reference to the appendedfigures, in which:

FIG. 1 shows a view of the mattress according to the invention, in whichthe first layer of the mattress is separate from the second layer of themattress;

FIG. 2 shows a cross section of a possible embodiment of the mattressaccording to the invention;

FIG. 3 shows a top part of a spring device for use in the mattressaccording to the invention;

FIG. 4 shows the spring device according to FIG. 3 in an unloaded and aloaded state;

FIG. 5 shows a side view of a part of the mattress according to theinvention, in which two spring devices according to FIGS. 3 and 4, whichare accommodated in the material of the mattress, can be seen.

FIG. 6 shows a cross section of a shock absorber for use in the springdevices according to the invention, the shock absorber comprising an aircylinder.

FIG. 7 shows a spring device comprising a shock absorber according toFIG. 6, in an unloaded and a loaded state;

FIG. 8 shows a cross section of a further variant of the shock absorberfor use in a spring device according to the invention;

FIG. 9 shows a spring-type device for use in the mattress according tothe invention, in an unloaded and a loaded state.

FIG. 1 shows the mattress 10 according to the invention. The mattress 10comprises a first layer or top layer 1, which is fixed on a second layeror bottom layer 2 when the mattress is in use. In FIG. 1, for the sakeof clarity, the layers 1, 2 are illustrated at a distance from eachother. Blind holes 3 for the accommodation of spring devices 4 areprovided in each of the layers 1, 2. A possible embodiment of saidspring devices is discussed further with reference to FIG. 3 and thefigures following it. The blind holes 3 are provided in such a way inthe first layer 1 and the second layer 2 respectively that the blindholes 3 in the first layer 1 connect to the blind holes 3 in the secondlayer 2. This means that the blind holes of the combined layers 1 and 2together form channels that extend over substantially the entirethickness of the mattress.

It can further be seen in FIG. 1 that the top side of the mattress, inother words the top side of the layer 1, forms a smooth surface. The topside is therefore not damaged, which means that the user cannot feel anyedges, uneven parts and the like on the top side of the mattress.

The mattress 10 according to the invention can be made in such a waythat the material of the first layer 1 differs from the material of thesecond layer 2. A plastic with a high degree of comfort, for example, isused for the first layer 1. An example of a suitable plastic is slowfoam. This plastic is relatively expensive. For the second layer 2, adifferent plastic can be used, one that is also suitable for a mattress,but in the case of which the comfort level can be lower, without theoverall comfort of the mattress 10 being adversely affected. Polyestercan be used as the material for the second layer 2.

A suitable material for the first layer 1 is, for example, slow foamF50. This material can be provided in any desired thickness, but itpreferably has a thickness of approximately 8 cm. The bottom layer 2 canbe made of, for example, polyester cold foam SG45. Said second layer 2can also be made in any suitable thickness. The bottom layer 2 is, forexample, made in a thickness of 10 cm.

The presence of the spring devices 4 in the mattress 10 according to theinvention makes it possible to obtain a better pressure distribution ofthe pressure exerted upon the top side of the mattress than is possiblein the prior art. A user will experience greater comfort as a result ofthis better pressure distribution. Greater comfort means, inter alia,that users with back and neck complaints are less subject to sleepdisturbances.

Research carried out at the Erasmus University in Rotterdam has shownthat a good pressure distribution can lead to improved comfort.

In the prior art it is usual to measure the pressure that a userexperiences from a mattress by means of a so-called ergo check. In theergo check the load placed on the body is measured by means of aso-called measuring sheet. This is a substantially flat device in whichfinely distributed sensors are provided. Typically, 684 sensors are usedin a measuring sheet, these sensors being distributed uniformly over thetest surface. With the aid of this measuring sheet, the average pressureand the maximum pressure that the user experiences per cm² on the skincan be measured.

In the prior art it is usual for the pressure experienced by the body tobe expressed in MmHg. By means of the mattress according to theinvention, measurement results are achieved with an MmHg varying between8.8 and 10.5 in the position when the user is lying on his/her back,while these values vary from 11.2 to 12.9 MmHg when the user is lying onhis/her side.

FIG. 2 shows a cross section of a possible embodiment of the mattress 10according to the invention. FIG. 2 shows a side view in cross section ofthe mattress. The mattress 10 according to FIG. 2 again comprises afirst layer 1, which is supported by a second layer 2. The first layer 1according to FIG. 2 is made of slow foam. Four holes 11 are made in thematerial over the width of the mattress 10. Said holes are used as airholes and have a diameter of typically 12 mm. In order further toimprove the pressure distribution over the top surface of the slow foam,notches are made in the slow foam, which notches extend along the lengthof the mattress. Such notches can also extend in the transversedirection of the mattress (not shown). The notches 12 that areillustrated in FIG. 2 typically have a depth of 40 mm.

FIG. 3 shows a top part of a first embodiment of a spring device 40according to the present invention. The spring device 40 comprises acoil spring 41, which on the inside is filled with an element made of afoam rubber, such as polyether. The element is indicated by referencenumeral 42. On the top side the spring device 40 is provided with adish-shaped end element 43. Both the coil spring 41 and the foam rubberelement 42 are fixed to this end element 43. The end element 43 acts asa tumbler. In other words, the end element 43 can follow deformations ofthe mattress. Through the presence of the end element 43, the materialof the mattress in which the spring device 40 is provided is preventedfrom being loaded very locally, for example by the end of coil spring41.

FIG. 4 shows the spring device 40 according to FIG. 3. FIG. 4 shows thespring device 40 in an unloaded state (on the left in the figure) and ina loaded state (on the right in the figure).

FIG. 5 shows a cross section of a part of a mattress 10 according to theinvention, which mattress comprises a first layer 1 and a second layer2, blind holes 3 being made in each of the layers, and the spring device40 according to FIGS. 3 and 4 always being provided in the channel thatis formed by a blind hole 3 in the first layer and a blind hole 2 in thesecond layer.

FIG. 6 illustrates an alternative shock absorber 52, for use for aspring device according to the invention, which shock absorber 52comprises an air cylinder. The shock absorber 52 is fixed at both endsto end elements 53. The shock absorber comprises a piston rod 54, whichcan move up and down in a cylinder 55. A piston element 56 is providedon the underside of the piston rod and connected in a close fit to theinside wall of the cylinder 55. For good functioning of the shockabsorber, an air hole 57 is provided in the cylinder wall, near thebottom side of said wall. The shock absorber 52 according to FIG. 6 isconnected by means of a snap closure to each of the end elements 53. Thesnap closure is indicated diagrammatically by the spherical element 58on both ends of the shock absorber 52.

FIG. 7 shows an alternative embodiment of a spring device 50, comprisinga coil spring 51 and a shock absorber 52 according to FIG. 6. The springdevice 50 is illustrated in the unloaded state on the left in FIG. 7 Thesame spring device 50 is illustrated in the loaded state on the right inFIG. 7.

FIG. 8 illustrates a third embodiment of a shock absorber 62. The shockabsorber 62 comprises a rubber element 63, which can deform whensubjected to load. The rubber element 63 is provided at both ends with abar or leg 64, which is connected by means of a snap closure to two endelements 63.

FIG. 9 illustrates a further variant of a spring device 60, composed ofthe shock absorber 62 according to FIG. 8 and a coil spring 61. Thespring device 60 is illustrated in the unloaded state on the left inFIG. 9. The same spring device can be seen in the loaded state on theright in FIG. 9.

As may be seen from the drawings, referring for example to end element53 as it is shown in FIG. 6 and to rubber element 63 as shown in FIG. 8,the spring devices employed in the practice of the invention can havedisc-shaped end elements, if desired.

Furthermore, the end elements can be pivotally attached to the shockabsorber, if desired. For example the end elements may pivot about asnap closure, if such is employed, as is shown particularly clearly forthe uppermost end elements 53 and 63, in FIGS. 6 and 8, respectively.

1. A mattress for use as a bed, the mattress comprising resilientmaterial, spring devices provided in the mattress to distribute pressureexerted upon the mattress, at least two layers placed one on top of theother, blind holes for the accommodation of the spring devices in atleast one of said two layers, the blind holes extending through said atleast one layer to the boundary between said one layer and another ofsaid at least two layers, wherein each said spring device comprises acoil spring element, a shock absorber operatively connected to said coilspring element and a disc-shaped end element on the end of the coilspring element.
 2. Mattress according to claim 1, wherein said shockabsorber is in the form of a substantially continuous element ofresilient material.
 3. Mattress according to claim 1, wherein said shockabsorber comprises polyether.
 4. Mattress according to claim 1, whereinsaid shock absorber comprises a rubber element.
 5. Mattress according toclaim 1, wherein said shock absorber comprises an air cylinder. 6.Mattress according to claim 5, wherein said spring devices aredistributed over the mattress, the spring characteristic of the springsvarying along the length of the mattress.
 7. Mattress according to claim6, wherein said first layer comprises a first material and the secondlayer comprises a second material, the first material and the secondmaterial differing from each other.
 8. Mattress according to claim 1,wherein at least one of the layers comprises slow foam.
 9. Mattressaccording to claim 8, having notches made in the slow foam on theoutside of the mattress, which notches extend in one or both of thelongitudinal direction or the traverse direction of the mattress. 10.Mattress according to claim 9, notches extend along a length ofapproximately 40 mm.
 11. Mattress according to claim 1, wherein at leastone of the layers comprises polyester.
 12. A mattress according to claim1 wherein the coil spring element has two ends and each spring deviceincludes a disc-shaped end element for each end of the coil springelement, the coil spring element being fixed at each end to a respectiveone of the disc-shaped end elements.
 13. Mattress according to claim 12,wherein each said shock absorber is fixed at both ends to the endelements of the spring devices.
 14. Mattress according to claim 13,wherein said shock absorber is hingedly connected to at least one of theend elements of the spring devices.
 15. Mattress according to claim 1,wherein the spring characteristic of the shock absorber varies along thelength of the mattress.
 16. A mattress according to claim 1 wherein eachend element is pivotally attached to a respective shock absorber.
 17. Amattress according to claim 16 wherein the pivotal attachment of eachend element to a respective shock absorber is effected by a snap closureand the end element is pivotable about the snap closure.
 18. Method forproducing a mattress, for use as a bed, the mattress being made ofresilient material, and spring devices being fitted in the mattress, inorder to distribute the pressure exerted upon the mattress, wherein saidmattress is constructed of at least two layers placed one on top of theother, blind holes being made in at least one of the layers, whereineach said spring device comprises a coil spring element, a shockabsorber operatively connected to said coil spring element and adisc-shaped end element on the end of the coil spring element andwherein said spring devices are provided in said blind holes, afterwhich said blind holes are covered by a second layer of the mattress.19. Mattress according to claim 18, wherein blind holes are provided inboth a first and a second layer of the mattress, and spring devices aresubsequently provided in the blind holes of the first layer of themattress, the spring devices then being covered by the second layer ofthe mattress, so that the blind holes of the first layer of the mattresslie in line with the blind holes of the second layer of the mattress.20. A mattress for use as a bed, the mattress comprising resilientmaterial, spring devices provided in the mattress to distribute pressureexerted upon the mattress, at least two layers placed one on top of theother, blind holes for the accommodation of the spring devices in atleast one of said two layers, the blind holes extending through said atleast one layer to the boundary between said one layer and another ofsaid at least two layers, wherein said spring devices each comprise acoil spring element and a shock absorber operatively connected to saidcoil spring element and wherein the shock absorber comprises an aircylinder.